If prices and wages are flexible, a decrease in aggregate demand will in the long run cause only a(n):

The economy is at full employment when

A) there are no unemployed workers. B) all unemployment is frictional or structural. C) there are fewer unemployed workers than available jobs. D) all unemployment is cyclical.

Tom is going to quit his job to pursue his PhD in economics, which will take him 6 years to complete. He currently makes $55,000 per year as a high school teacher

While going to school, he will receive a stipend of $24,000 per year plus $6,000 per year to help cover food and rent. His living expenses are the same regardless of what he does. What is Tom's opportunity cost of pursuing his PhD? A) $150,000 B) $180,000 C) $186,000 D) $330,000